Developing web application for deaf users: ordering street food

Background: Deaf individuals who use sign language (SL) as their primary language often encounter communication barriers in everyday service interactions dominated by spoken or written language. These challenges are particularly evident in street-food settings, where ordering requires rapid and precise communication. This study developed and evaluated a visual-first, multimodal web application to support street-food ordering for Deaf users. Methods: The application integrated food images, structured menu selection, SL videos, text, and audio output to facilitate communication with hearing vendors. Development followed an iterative User-Centered Design (UCD) process involving expert review, pilot testing, and final usability evaluation with 60 Deaf participants. Quantitative and qualitative data were collected to assess usability and user experience. Results: Participants reported high levels of agreement regarding accessibility, visual clarity, and comprehension of SL content. Structured menus, realistic food images, concise SL videos, and audio output were perceived as helpful for constructing and communicating orders. However, lower ratings were observed for learnability and button operation. Qualitative findings further identified challenges related to interaction flow, visibility of interactive elements, and interface complexity. Discussion: The findings suggest that visual-first, multimodal interfaces can improve perceived communication efficiency and support more accessible food-ordering interactions for Deaf users. The study highlights the importance of Deaf-informed, culturally grounded design and demonstrates how iterative UCD processes can identify both usability benefits and design trade-offs. These findings provide practical guidance for the development of accessible communication technologies in everyday service contexts. The application is available at: https://supachan.github.io/street_food_ordering/index.html.